Examination of lateral deviation of a projectile subjected to internal gyroscopic forces

Abstract

The need for lateral travel can arise in a simple projectile either due to the target moving or to a transverse external force that moves the projectile. By the use of internal moving parts, a force in the lateral direction can be created, thus changing the flight trajectory of the projectile. Therefore, the possibility of the use of an internal gyroscopic force derived from a rotating disk could be used to counteract such activity. In this study, three internal swing masses attached at the end of a mass-less rod are located on the points of an equilateral triangle centered about the major axis of the projectile. The rotation of mass generates a normal acceleration and a subsequent force and torque upon the projectile. The force from combined movements of the masses can be used, to a small degree, to control the movement of the projectile. A model for this movement is derived mathematically and simulated on the computer using commercial-available software and a developed code. For the cases examined, the projectile moved cyclically about the axis or deviated with a relatively even slope away from the axis. With these models, a parametric study is conducted with predetermined changes. The parametric study focused on actuating each mass in sequence or changing the initial weight of the mass and starting position in relation to the projectile. Two different simulation methods are used. A MATLAB program is created for the developed model for the equations of motion to simulate the flight of the projectile. Also a model is created in the MSC Adams software to simulate the projectile flight. The results from the simulation for the project are compared for differences between physical conditions and simulation software used. The results of this study show that the projectile could move in a lateral direction in a controlled manner. But the overall movement is minimal when compared to the size of the projectile or the distance traveled. While this application may not be suited for use in small projectiles, it may hold merit for use with larger craft or re-entry vehicles.